1. Field of the Invention
The invention relates to a system for improving fuel flow in internal combustion engines, and more particularly to a system and method for the induction of a fluid in an internal combustion engine that enhances valve cylinder filling and scavenging to provide for improved charge stratification and efficient combustion.
2. Background
Obstacles to the efficient flow of fluid to the combustion chambers of internal combustion engines exist in even the best of current inlet porting systems. Generally, a fluid, such as a fuel/air mixture, that is introduced into an intake port must navigate around the valve stem of the intake valve before the fuel/air mixture enters the combustion chamber. Because the valve stem asserts itself in the middle of the fluid stream, vortices and fluid disruptions present themselves and serve as obstacles for impeding the flow of the fluid through the intake port. In addition, the fluid stream must redirect itself around the back face of the valve in order to fill the combustion chamber. Since the intake port is necessarily disposed at an angle to the valve and its valve stem in conventional engines, the back face of the valve will always deflect the fluid stream to one side of the intake port thereby rendering the opposite side of the intake port inaccessible as flow of fluid enters the combustion chamber. This problem is especially acute at lower valve openings, for example, in the critical overlap period that exists when combustion residuals from the previous combustion cycle are being swept out by incoming fluid flow. Inefficient mixing of fuel and air leads to incomplete or inefficient combustion in the engine's combustion chamber.
3. Related Art
Various intake systems in multi-cylinder combustion engines have employed the use of dual inlet ports for controlling the passage of a fuel-air mixture to the combustion chamber. U.S. Pat. No. 4,469,063 issued Sep. 4, 1984 to Sugiura et al. discloses a complete inlet manifold and port system specifically designed for carbureted engines and for engines utilizing a single inlet valve. As illustrated in FIGS. 1 and 2, the intake port structure consists of a primary passage 18 that interfaces with the side wall of a secondary passage 20 in tangential relation to the combustion chamber, and is angled downwardly at a small acute angle relative to the plane of the intake valve seat 14. In order for the secondary passage to create a helical swirling motion of the fuel-air mixture in the combustion chamber, a flow deflector wall 22 is provided in the cylinder head which extends into the secondary passage 20 above and upstream of the intake valve 6. The resulting cross-flow and collision of the fuel-air mixture from each of the primary and secondary intake passages, and hence the destruction of the swirling effect, is avoided by providing a groove 26 in the inner surface 22u of secondary passage 20 which extends from the first outlet port 18b to the flow deflector wall 22 at a point adjacent to the valve seat 14. However, this design deliberately crosses the high-velocity, small (primary) inlet port, fuel-air mixture stream with that of the larger (secondary) inlet port so that the high-velocity stream redirects the larger stream by interference. The manner in which this is done interrupts any swirl created for the fluid and results in significant energy losses for the fluid stream entering the combustion chamber.
U.S. Pat. No. 5,309,880 issued May 10, 1994 to Mazzella et al. discloses a dual intake port in a multi-cylinder reciprocating internal combustion engine (see FIGS. 1 and 2). The intake port consists of primary and secondary port passages, 22 and 24, respectively, that interface the stem of each intake valve of the engine. The dual port passages are parallel to each other and approach the intake port zone from a common direction at substantially right angles. While each of the primary and secondary port passages are oriented in tangential relationship to the valve stem 16, the flow pattern created for the fuel-air mixture passing through the passages (when the secondary throttle valve is open) is neither symmetrical nor in the form of a helical swirling action thereby resulting in energy loss to the fuel injection system.